Subject matter of the invention is a method and an arrangement for driving door installations wherein the acquisition and evaluation of persons in front of door installations is carried out with the goal of opening and closing door installations as a function of persons moving in front of the door installations.
Such method is disclosed for example with the subject matter of U.S. Pat. No. 4,249,207 A. In this known arrangement a so-called video entrance alarm is generated if one or several persons enter a specific monitoring area. For this purpose the monitoring area is divided into a specific number of subareas and an investigation is carried out regarding the presence or absence of persons in these cell-like subareas. According to the condition detected a corresponding alarm is subsequently triggered.
The invention is based on the task of further developing a method and a device of the above cited type such that with minimum expenditures one or several door installations in a building can be controlled as a function of the location, the direction of movement and the number of persons in front of these door installations.
To solve the task posed the invention is characterized by the technical teaching of claim 1 or claim 18.
It is a characteristic of the invention that initially in a first process step the space in front of the door installation is acquired with at least one video camera and specifically in such manner that first only the xe2x80x9cempty spacexe2x80x9d is acquired. By the term xe2x80x9cempty spacexe2x80x9d is understood that this space is acquired at a point in time at which no or only few motions by persons take place in this space. For example, the space to be monitored in front of the door installation is initially acquired by the video camera at a point in time at which substantially no motion takes place in this space, for example early in the morning or late in the evening wherein the stationary objects usually disposed in this space, such as for example planters, lampposts and the like, are acquired by the videocamera and the system learns the location and the configuration of these stationary objects.
As empty space is here defined if in the space to be monitored within a time period of approximately 3 to 4 seconds no motion of any kind takes place or is detected. Based on this, a so-called reference image is obtained which serves as a reference model of the empty space, i.e. the empty space with all its objects is stored as a model in a memory and serves as a measure of comparison.
In a preferred embodiment of the present invention it is provided that the videocamera examines approximately every 3 to 4 seconds whether or not the space is empty andxe2x80x94should this be the casexe2x80x94creates a new reference model of the empty space. It is herein important that in these time intervals a complete new model of the empty space is not always created but rather that in an iterative approximation process this empty space is continuously approximated to the actual conditions. This means in practice that if no motion has been detected within the last 3 to 4 seconds, but new objects have been recognized as being stationary in the empty space, that this model of the empty space is only expanded and supplemented by the newly added stationary object.
After in a first process step a model of the empty space has been generated, the empty space is now continually and regularly observed with the videocamera in order to determine whether or not the space is in fact empty or whether a motion is taking place in this space.
If a motion is detected in this space, which can take place by evaluating the video image or can also be determined by including further signal sources, such as for example infrared detectors, weight sensors and ultrasound sensors, in the case of a non-empty space, i.e. in the event of acquired motion, determination takes place in a subsequent process step of whether or not the moving object is an object authorized to use the door installation and also intending to do so, for example a person.
For this purpose a pattern analysis of the moving contour is carried out, i.e. a moving person is only recognized as being a person if the moving contour covers a specific area and form and notion of the acquired contour resemble those of a human being. This means, for example, a moving baby carriage is not recognized as a moving person because the form of the baby carriage does not correspond to that of a person. However, the person pushing the baby carriage is recognized.
Moving animals (for example dogs or cats) are not recognized as moving person due to the differing motion contour and therefore the door installation is consequently also not driven unless the use of the door by these animals is intended.
After the acquisition and analysis of the motion contour in the previously described second process step, in the third process steps, as cited above, the motion contour of the person is analyzed. If it is recognized that this case is one of a moving person, the location of the moving person is determined in a fourth process step. It is herein important that first the distance of the person from the videocamera is determined. Based on this distance measurement the precise location in the space can subsequently be calculated, i.e. it is possible to specify in terms of coordinates precisely where the person in front of the door installation is located.
In a preceding process step it is also specified that the videocamera has, of course, also acquired, together with the acquisition of the empty space, a plan model of the space with the position of the door, and that this plan model is stored in a memory.
In a further, differing embodiment example it is provided that the plan model is not acquired by the camera (potentially also by another camera), but rather that the plan model is written through manual entry at a corresponding terminal into the memory of the computer where it is subsequently stored.
Based on the coordinates of the moving person and based on the comparison with the stored plan model, it is now readily possible to acquire the type and direction of movement of the moving person in front of the door installation.
In a further process step now the monitoring area is divided into different regions wherein at least one region is defined as that, upon entrance of which, the door installation is driven while other regions are present which do not lead to the driving of the door installation.
Only if the acquired motion model predicts that the person intends to enter or is entering the region of the monitoring area associated with the door installation, is an opening signal output to the door installation and the door installation is opened.
This region model has the advantage that the door installation is not opened if the videocamera, in connection with the above listed regions, acquires for example a person running past the door installation, who, based on the direction of movement and rate of movement, apparently does not intend to walk into the door installation. In this way with the novel process model it is achieved that the door installation is only driven to open or close if a person moving in front of the door installation is heading toward the door installation at the appropriate speed and direction of movement.
The opening and closing of door installations from the inside of the building takes place analogously so that on the inside of a building a corresponding monitoring installation can also be disposed which accomplishes the intelligent opening and closing of the door installation as a function of a person leaving the building.
In a further embodiment of the present invention it is provided that in a subordinated process step a determination takes place of the width of the person who is heading toward the door installation. It can herein be determined for example whether the person is pushing a baby carriage, whether the person is carrying several packages or has some other unusual opening requirement of the door. The wider the person, the wider the door installation can be opened and the door installation can accordingly only be opened far enough to ensure the easy and comfortable passage of the person moving in front of the door installation. For this entails the advantage that the door is only opened so far that the unnecessary heat and convective flow loss from the building to the outside is avoided.
It is likewise provided in a further development of the present invention that the start and/or the speed of door opening and/or door closing is driven as a function of location, direction of movement and especially by the rate of movement of the persons approaching the door installation. A person approaching the door installation rapidly and whose presence is acquired in the triggering door region, leads to a more rapid opening of the door wings than a person approaching relatively slowly in comparison.
In a further development of the present invention it is provided that light reflections in the monitoring area, for example on the floor, in the region of the walls of the door installations or on other containment walls are eliminated thereby that the videocamera operates with a polarization filter.
The potential casting of shadows by the persons to be monitored is recognized and eliminated thereby that particular recognition criteria can be associated with the shadow and thus can exclude the casting of a shadow such that effectively only the motion contour of the person to be monitored itself is acquired but not its light shadow.
In a preferred embodiment of the present invention (arrangement) it is preferred if the camera is disposed approximately diametrically with respect to the door installation but in a somewhat raised position of, for example, 5 m above the ground because with this elevated position diametrically opposite to the door installation the advantage is achieved that with a camera disposed as high as possible a relatively small angle of view of the camera onto the person to be monitored is achieved, i.e. an extremely high-resolution recognition of the persons moving below the camera is possible.
It is understood that the invention is not limited thereto, several cameras can also be disposed whose angles of view also intersect wherein the camera image of several cameras is evaluated.
It is also possible to use a stereo camera instead of a single monocular videocamera. Assuming a predefined image area the image of the one camera can be transferred to the image to be expected from the second camera and by comparison of the calculated and effectively received image conclusions can be drawn regarding the presence and/or changes of objects in the image area.
Therein the predefined image area is adapted or newly selected in the course of successive image analyses based on the results available in each instance. It is possible to adapt or newly select further parameters such as for example image segment, frequency of image analyses, image resolution in the course of successive image analyses based on the particular available results wherein in order to achieve absolute operational reliability the data of elements multiply provided (for example several cameras) are utilized.
It is also provided that in addition to the videocamera, which opposes the door installation diametrically, still further cameras are disposed which, for example, are disposed laterally in front of the door installation.
In a further embodiment of the invention it is provided that with a camera disposed relatively low, for example at a level of approximately 2 m, a high observation point is achieved thereby that the camera image is deflected via a mirror disposed at a high level and the monitoring area is acquired from this mirror.
The subject matter of the present invention is evident not only based on the subject matter of the individual patent claims but rather based on the combination with one another of the individual patent claims.
All specifications and characteristics disclosed in the documents, including the abstract, in particular the spatial implementation depicted in the drawings are claimed as being essential to the invention to the extent they are novel individually or in combination relative to prior art.
In the following the invention will be explained in further detail in conjunction with the drawings representing only one embodiment path. Herein in the drawings and their description further characteristics and advantages essential to the invention are evident.